Felix Glyukman told SBS he and his boyfriend, Islam Abdullabeckov were detained for about three hours, after trying to leave flowers and a sign reading "Love wins" outside the US embassy in Moscow.
"We were in shock. And we decided to go to the embassy with flowers and candles and a poster," he said.
He said he does not know why he and his boyfriend were singled out.
"There were many people and many flowers and candles. But the policeman grabbed the poster and told us we have to leave, but Islam (Abdullabeckov) said we didn't want to and (the officer) grabbed him, and put us in the car."
Mr Glyukman told SBS police accused them of committing an 'administrative offence'.
He said he and his partner had not intended to make a political statement, only to pay their respects to the victims of the Orlando massacre.
"This is very strange, and very sad, I think," he said.
The two men posted photos of their arrest on Facebook, including one apparently taken inside the police car.
Felix Glyukman (right) told SBS he still doesn't know why they were singled out by Moscow police Source: Supplied
"This is completely surreal," Mr Abdullabeckov wrote in one caption.
Mr Glyukman added: "We tried to leave flowers and a sign at the embassy - we did not succeed."
The incident did not deter people who continued to leave tributes outside the embassy in Moscow on Tuesday. Footage showed people leaving floral tributes, and signs with messages such as, "The risk of being free", as Russian police watched on.
'We have never experienced this kind of thing before', Felix Glyukman told SBS. Source: Supplied
The massacre at Orlando's Pulse nightclub on Sunday killed 50 people and sparked an outpouring of grief around the world. Russian President Vladimir Putin denounced the killings as "a barbaric crime".
However, Russian law systematically bans protests over gay rights, and the country's LGBTQI continues to suffer widespread discrimination.
Homosexuality remained a crime in Russia until as recently as 1993, and was categorised as a mental illness until 1999.
